如果DAO不是无状态的，Glassfish不会启动EntityManager [英] Glassfish doesn't bring up EntityManager if DAO is not Stateless

问题描述

我有一个带有EJB模块的EAR应用程序，它包含一个持久性单元和许多EJB（作为服务和DAO层）。

  @Stateless 
 public class BranchDAO {
 @PersistenceContext 
 private EntityManager entityManager; 
} 
  

不建议使用DAO作为无状态bean。所以我使用CDI创建了这个注释：

  @Dependent 
 @Stereotype 
 @Target（ElementType.TYPE ）
 @Retention（RetentionPolicy.RUNTIME）
 public @interface DAO {
} 
  

将我的DAO更改为不使用 @Stateless ：

  @DAO 
 public class BranchDAO {
 @PersistenceContext 
 private EntityManager entityManager; 
} 
  

但Glassfish在应用程序启动时不会显示实体管理器。当我调用DAO时，实体管理器处于非法状态。

java.lang.IllegalStateException：无法检索UnitName的EntityManagerFactory null

这个错误只出现在Glassfish 3中，但不在JBoss AS 6中。使用JBoss AS 6我可以看到Hibernate日志初创公司（但我没有看到他们与Glassfish）。

作为一个临时解决方案，我创建了一个无状态bean，其内容如下。它不是漂亮的解决方案，但在Glassfish中运行良好。

  @Stateless 
 @Startup 
 public class AutoStartEntityManager {
 
 @PersistenceContext 
私人EntityManager entityManager; 
 
 
 
 
 
 
所以，我可以如何强制Glassfish启动EntityManager我在DAO中没有使用 @Stateless  
   试试显式指定unitName：
 
 $ pre code $ @PersistenceContext（unitName =yourJPAUnitName）
私有EntityManager管理器; 
  

（一个旁注 - 你确定你需要依赖范围的DAO吗？不应该是单例？）

I have an EAR application with an EJB module, that contains one persistence unit and many EJBs (as service and DAO layer).

@Stateless
public class BranchDAO {
    @PersistenceContext
    private EntityManager entityManager;
}

But DAOs as Stateless beans are not recommended. So I create this annotation using CDI:

@Dependent
@Stereotype
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface DAO {
}

After my DAO is changed to not use @Stateless:

@DAO
public class BranchDAO {
    @PersistenceContext
    private EntityManager entityManager;
}

But the Glassfish doesn't bring up the entity manager when the application starts. And when I call the DAO, the entity manager is in an illegal state.

java.lang.IllegalStateException: Unable to retrieve EntityManagerFactory for unitName null

This error only occurs in Glassfish 3, but not in JBoss AS 6. Using JBoss AS 6 I can see the Hibernate logs in startup (but I don't see them with Glassfish).

As a temporary solution I created an Stateless bean with the content below. It's not beautiful solution, but works fine in Glassfish.

@Stateless
@Startup
public class AutoStartEntityManager {

    @PersistenceContext
    private EntityManager entityManager;

}

So, how I can force Glassfish to bring up EntityManager when I'm not using @Stateless in my DAO?

解决方案

Try specifying explicitly the unitName:

@PersistenceContext(unitName="yourJPAUnitName")
private EntityManager manager;

(A sidenote - are you sure you need the DAO in dependent scope? Shouldn't it be singleton?)

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